The overall objective of the project is to elucidate the details of mRNA biogenesis in order to build a framework for an understanding of the manner in which gene expression is controlled. Adenovirus mRNA production will be utilized as a model system since the processes involved in adeno mRNA formation all appear to be analogous to those of the uninfected cell. The availability of large amounts of a well mapped DNA genome and the fact that a large proportion of infected-cell RNA synthesis is viral offer clear advantages to use of this system. Two general areas will be investigated: the role of internally methylated residues (m6A) in mRNA formation and a characterization of the nature of premature transcription termination. Specifically, the locations of m6A residues in mRNA, the conservation of m6A residues, and the timing of the addition of m6A residues will be determined, primarily with regards to processing of nuclear RNAs. Premature transcription termination from the late adeno promoter at map position 16 may be analogous to attenuation in bacteria. Studies on this subject will include a) the development of a quantitative assay for premature termination, b) an analysis of the structure of prematurely-terminated transcripts and c) an analysis of other adenovirus transcription units for premature termination.